/Engine/Source/Editor/BlueprintGraph/Classes/K2Node_FunctionEntry.h
Modifies the default value of an existing pin on the node, this will update both the UserPinInfo and the linked editor pin
virtual bool ModifyUserDefinedPinDefaultValue ( [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [FUserPinInfo](API\Editor\BlueprintGraph\FUserPinInfo) > PinInfo, const [FString](API\Runtime\Core\Containers\FString) & NewDefaultValue )